/*
 Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
 

  The MySQL Connector/J is licensed under the terms of the GPLv2
  <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most MySQL Connectors.
  There are special exceptions to the terms and conditions of the GPLv2 as it is applied to
  this software, see the FLOSS License Exception
  <http://www.mysql.com/about/legal/licensing/foss-exception.html>.

  This program is free software; you can redistribute it and/or modify it under the terms
  of the GNU General Public License as published by the Free Software Foundation; version 2
  of the License.

  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU General Public License for more details.

  You should have received a copy of the GNU General Public License along with this
  program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth
  Floor, Boston, MA 02110-1301  USA



 */

package com.mysql.jdbc.interceptors;

import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Properties;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.ResultSetInternalMethods;
import com.mysql.jdbc.Statement;
import com.mysql.jdbc.StatementInterceptor;

public class SessionAssociationInterceptor implements StatementInterceptor {

	protected String currentSessionKey;
	protected final static ThreadLocal sessionLocal = new ThreadLocal();
	
	public static final void setSessionKey(String key) {
		sessionLocal.set(key);
	}
	
	public static final void resetSessionKey() {
		sessionLocal.set(null);
	}
	
	public static final String getSessionKey() {
		return (String)sessionLocal.get();
	}
	
	public boolean executeTopLevelOnly() {
		return true;
	}

	public void init(Connection conn, Properties props) throws SQLException {

	}

	public ResultSetInternalMethods postProcess(String sql,
			Statement interceptedStatement,
			ResultSetInternalMethods originalResultSet, Connection connection)
			throws SQLException {
		return null;
	}

	public ResultSetInternalMethods preProcess(String sql,
			Statement interceptedStatement, Connection connection)
			throws SQLException {
		String key = getSessionKey();
		
		if (key != null && !key.equals(this.currentSessionKey)) {
			PreparedStatement pstmt = connection.clientPrepareStatement("SET @mysql_proxy_session=?");
			
			try {
				pstmt.setString(1, key);
				pstmt.execute();
			} finally {
				pstmt.close();
			}
			
			this.currentSessionKey = key;
		}
		
		return null;
	}

	public void destroy() {
		
	}
}